About the temperature converter
Temperature is the one conversion on this site that is not a multiplication. Celsius and Fahrenheit put their zero points in different places, so converting between them needs an offset as well as a ratio - which is why multiplying a temperature by a factor gives the wrong answer.
Kelvin is the exception that makes the arithmetic simple. Its zero is absolute zero, the point where there is no thermal energy left to remove, so Kelvin has no negative values and scales proportionally.
Frequently asked questions
- Is anything I enter sent anywhere?
- No. Every conversion runs inside your browser. Nothing you type is uploaded, stored or logged, and the page keeps working with the network disconnected.
- What is the formula for Celsius to Fahrenheit?
- Multiply by 9/5 and add 32. Going the other way, subtract 32 first and then multiply by 5/9 - the order matters, and getting it backwards is the usual mistake.
- Is there a temperature where Celsius and Fahrenheit agree?
- Yes, at −40. It is the only point where the two scales give the same number, which makes it a useful check on any conversion tool.
- Why does Kelvin have no degree symbol?
- Because it is an absolute scale rather than a scale of degrees relative to an arbitrary zero. It is written 300 K, not 300 °K.
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How your data is handled
Everything happens on your device. There is no upload, no storage and no logging. Closing the tab clears everything you entered.